Surgical stapler

ABSTRACT

A surgical stapler is disclosed which includes a first body portion supporting an anvil plate defining a fastener forming surface, and a second body portion configured to releasably mate with the first body portion. A disposable loading unit is removably supported in the second body portion and includes a cartridge defining a plurality of slots, a plurality of surgical fasteners disposed in the slots, a plurality of ejectors positioned adjacent the surgical fasteners, and a wedged actuator configured to enter into and translate through the cartridge to sequentially interact with the ejectors. An elongated actuation member is mounted for longitudinal movement within the second body portion and is releasably engagable with the wedged actuator, whereby longitudinal movement of the actuation member causes the wedged actuator to interact with the ejectors, driving the surgical fasteners from the cartridge to be formed against the anvil plate.

[0001] This application is a Continuation of U.S. patent applicationSer. No. 09/366,583, which was filed on Aug. 4, 1999, which is aDivision of U.S. patent application Ser. No. 08/549,580, filed Oct. 27,1995 and are here incorporated by reference.

BACKGROUND

[0002] 1. Technical Field

[0003] This application relates to surgical staplers, and moreparticularly, to an apparatus for sequentially applying a plurality ofsurgical fasteners to body tissue.

[0004] 2. Background of Related Art

[0005] Surgical devices wherein tissue is first grasped or clampedbetween opposing jaw structure and then joined by means of surgicalfasteners are well known in the art. In some instruments a knife isprovided to cut the tissue which has been joined by the fasteners. Thefasteners are typically in the form of surgical staples however, twopart polymeric fasteners are also utilized.

[0006] Instruments for this purpose can comprise two elongated memberswhich are respectively used to capture or clamp tissue. Typically, oneof the members carries a cartridge which houses a plurality of staplesarranged in at least two lateral rows while the other member comprisesan anvil which defines a surface for forming the staple legs as thefasteners are driven from the cartridge. Where two part fasteners areused, this member carries the mating part, e.g. the receiver, to thefasteners driven from the cartridge. Generally, the stapling operationis effected by a pusher which travels longitudinally through thecartridge carrying member, with the pusher acting upon the staples tosequentially eject them from the cartridge. A knife may travel with thepusher between the staple rows to longitudinally cut and/or open thestapled tissue between the rows of staples. Such instruments aredisclosed in U.S. Pat. No. 3,079,606 and U.S. Pat. No. 3,490,675.

[0007] A later stapler disclosed in U.S. Pat. No. 3,499,591 applies adouble row of staples on each side of the incision. This is accomplishedby providing a cartridge assembly in which a cam member moves through anelongate guide path between two sets of staggered staple carryinggrooves. Staple drive members are located within the grooves and arepositioned in such a manner so as to be contacted by the longitudinallymoving cam to effect ejection of the staples. Other examples of staplersare disclosed in U.S. Pat. Nos. 4,429,695, 5,065,929, and 5,156,614.

[0008] Many of the prior art linear stapling devices discussed aboveinclude a significant number of moving parts, small components andmachined structural elements that are costly to fabricate and timeconsuming to assemble. These factors add to the overall cost of thestapling devices and thus increase the costs incurred by hospitals andhealth care professionals, and ultimately, the patient upon which thedevices are utilized. A linear stapler that could be manufactured andassembled less expensively would provide great benefits.

SUMMARY

[0009] The subject application is directed to a linear surgical staplerthat is constructed from fewer, less expensive components than knownprior art staplers configured to sequentially apply a plurality ofsurgical staples to body tissue. The stapler includes a first bodyportion supporting an anvil plate which defines a fastener formingsurface and a second body portion configured to releasably mate with thefirst body portion. In the detailed description which follows, the firstand second body portions of the stapler are also referred to as the“anvil half-section” and “cartridge half-section”, respectively.

[0010] A disposable loading unit is removably supported in the secondbody portion and includes a cartridge defining a plurality of slots anda tissue contacting surface, a plurality of surgical fasteners disposedin the slots of the cartridge, a plurality of ejectors or pusherspositioned adjacent the surgical fasteners. A wedged actuator providedin the disposable loading unit is positioned and configured to enter andtranslate through the cartridge to sequentially interact with thepushers.

[0011] The stapler in a preferred embodiment, further includes anelongated actuation member mounted for longitudinal movement within thesecond body portion and releasably engagable with the wedged actuator,whereby longitudinal movement of the actuation member causes the wedgedactuator to interact with the ejectors, driving the surgical fastenersfrom the cartridge to be formed against the anvil plate.

[0012] The first body portion preferably includes an elongate anvilsupport member and a pivoting lever handle. The anvil plate ispreferably formed separate from the anvil support member and includes aplurality of staple forming pockets defining the anvil forming surface.The anvil plate also includes means for engaging the anvil supportmember during assembly of the surgical stapler to securely fasten theanvil plate to the support member. A notched area is defined adjacent aproximal end of the anvil support member and correspondingly positioneddetents are formed adjacent a proximal end of the second body portion.The notched area and the detents cooperate to facilitate relativepivotal movement of the first and second body portions when they aremated with one another.

[0013] Preferably, a pair of upstanding flanges are formed on thedisposable loading unit proximal of the tissue contacting surfacethereof. The flanges define a structural tissue stop to limit themovement of body tissue. The flanges are also dimensioned to engage apair of corresponding apertures formed in the anvil plate to maintainthe first and second body portions in alignment with one another whenthe surgical stapler is in a closed or clamped position.

[0014] The wedged actuator of the disposable loading unit is preferablymonolithically formed from a planar piece of sheet metal during astamping process and includes a planar base and a pair of upstandingparallel cam wedges. An upturned flange is formed at a distal end of theactuation member for releasably engaging a complementary slot formed inthe base of the wedged actuator. The wedged actuator preferably furtherincludes an upstanding support flange to which a knife blade isfastened. The knife blade is provided to form an incision in the stapledbody tissue.

[0015] A retaining channel depends from a distal end of the second bodyportion for supporting the disposable loading unit Preferably, thedisposable loading unit and the retaining channel include complementaryengagement structures for releasably securing the disposable loadingunit in the retaining channel. Opposed bearing structures are formed inthe retaining channel at a proximal end thereof for abutting the anvilsupport beam when body tissue is clamped between the anvil plate and thetissue contacting surface of the cartridge. The bearing structures serveto inhibit the anvil support beam from bending as a result of thecompressive forces generated during clamping.

[0016] Further features of the surgical apparatus of the subjectapplication will become more readily apparent to those skilled in theart from the following detailed description of the apparatus taken inconjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Various embodiments of the surgical stapling apparatus of thesubject application will be described hereinbelow with reference to thedrawings wherein:

[0018]FIG. 1A is a perspective view of a surgical stapling apparatusconstructed in accordance with a preferred embodiment with the clampinghandle thereof disposed in an upright open position;

[0019]FIG. 1B is a perspective view of the surgical stapling apparatusillustrated in FIG. 1A with the clamping handle disposed in a closedposition;

[0020]FIG. 2 is an exploded perspective view of the surgical staplingapparatus of FIGS. 1A and 1B;

[0021]FIG. 3 is a perspective view of the lower body portion of thesurgical stapling apparatus of FIGS. 1A and 1B;

[0022]FIG. 4A is a top plan view of the retention channel of thesurgical stapling apparatus of FIGS. 1A and 1B;

[0023]FIG. 4B is a side elevational view of the retention channel shownin FIG. 4A;

[0024]FIG. 4C is a perspective view of the retention channel of FIGS. 4Aand 4B with the disposable loading unit retained therein;

[0025]FIG. 5 is an enlarged perspective view, with parts separated forease of illustration, of the disposable loading unit and actuationassembly of the surgical stapling apparatus of the subject application;

[0026]FIG. 5A is a cross-sectional view showing the engagement of thecartridge lip and the retention channel;

[0027]FIG. 6A is a perspective view of the actuation sled of thedisposable loading unit shown in FIG. 5 in a pre-formed condition;

[0028]FIG. 6B is a perspective view of the actuation sled shown in FIG.6A in a formed condition with the knife blade separated therefrom forillustrative purposes;

[0029]FIG. 6C is a perspective view of the formed actuation sled shownin FIG. 6B with the knife blade mounted to the blade support portionthereof;

[0030]FIG. 7 is a plan view of the preformed anvil plate which ismounted to the anvil support beam of the upper body portion of thestapling apparatus shown in FIGS. 1A and 1B;

[0031]FIG. 8 is a cross-sectional view of the preformed anvil platetaken along line 8-8 of FIG. 7;

[0032]FIG. 9 is a front end view of the preformed anvil plateillustrated in FIGS. 7 and 8;

[0033]FIG. 10 is a perspective view of the upper body portion of thesurgical stapling apparatus of FIGS. 1A and 1B with an enlargedlocalized view of a distal portion thereof illustrating the connectiveengagement between the anvil plate and the anvil support beam;

[0034]FIG. 11 is an exploded perspective view of an embodiment utilizinga lockout mechanism to prevent reactuation of the apparatus;

[0035]FIG. 11A is an enlarged cross-sectional view of the T-shapedmember of the lockout mechanism;

[0036]FIG. 12 is an enlarged perspective view of the actuation channelhaving an edge for engagement by the hook of the lockout mechanism;

[0037]FIGS. 13 and 13A are side views of the lockout mechanismillustrating its movement from a non-engaged to an engaged position;

[0038]FIG. 14 is a side elevational view in cross-section of thesurgical stapling apparatus of the subject application with theactuation sled disposed in a pre-actuated proximal position;

[0039]FIG. 15 is a side elevational view in cross-section of thesurgical stapling apparatus of the subject application with theactuation sled disposed in a partially advanced position; and

[0040]FIG. 16 is a side elevational view in cross-section of thesurgical stapling apparatus of the subject application with theactuation sled advanced to the distal end of the cartridge at theconclusion of a staple firing procedure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0041] In the drawings and in the description which follows, the term“proximal”, as is traditional, will refer to the, end of the apparatuswhich is closer to the operator, while the term “distal” will refer tothe end of the apparatus which is further from the operator.

[0042] Referring now to the drawings wherein like reference numeralsidentify similar structural elements, there is illustrated in FIGS. 1Aand 1B a surgical stapling device constructed in accordance with apreferred embodiment and designated generally by reference numeral 10which includes a cartridge half section 11A and an anvil half section11B. As will become readily apparent to those having ordinary skill inthe art, surgical stapler 10 is constructed in such a manner so as tosubstantially reduce the costs associated with its fabrication andassembly as compared to prior art linear staplers.

[0043] Referring to FIGS. 2 and 3, surgical stapler 10 includes a bodyportion 12 defining a handle for grasping and supporting the device. Aretaining channel 14 is mounted in the interior cavity 15 of bodyportion 12 adjacent the distal end thereof. Retaining channel 14 isdimensioned and configured to support a disposable loading unit 20, asillustrated in FIG. 4C.

[0044] As shown in FIG. 5, the disposable loading unit 20 includes acartridge 22 having a plurality of slots which support a correspondingnumber of surgical staples 24, a plurality of staple pushers or ejectors26 adapted and configured to eject the staples from the slots when actedupon by a staple driving force, and an actuation sled 28 which ismounted to translate through cartridge 22 in a longitudinal direction totransmit a staple driving force to the ejectors. The cartridge ispreferably composed of liquid crystal polymer material; although othermaterials are contemplated. The cartridge 22 has a lip 23 which engagesthe retention channel 14 to prevent inward rotation of the cartridge(see FIG. 5A).

[0045] As best seen in FIG. 6A, actuation sled 28 is preferablymonolithically formed from a single piece of sheet metal or a similarmaterial which is folded into the desired structural configuration shownin FIG. 6C. In this configuration, actuation sled (staple actuator) 28defines a base portion 30, two upstanding cam wedges 32 and 34, and anupstanding shank 35 which supports a knife blade 36. Knife blade 36 ispreferably spot welded to shank 35, although other known fasteningmethods may be employed. As illustrated in FIG. 6B, a weldment port 37and a winglet 39 are provided to facilitate the proper alignment andcohesion of knife blade 36 to shank 35 during fabrication. Cam wedges 32and 34 are staggered with respect to one another so that one leads theother throughout the sled's translation through cartridge 22. In doingso, the staple driving forces within cartridge 22 remain balanced duringa staple driving operation. Longitudinal slots 22 a and 22 b accommodatethe longitudinal translation of cam wedges 32 and 34, while slot 22 caccommodates the longitudinal translation of shank 35 (see FIG. 5).Although illustrated with a knife, it is also contemplated that theapparatus can be provided without a knife bade and therefore wouldstaple tissue without making an incision.

[0046] The base portion 30 of actuation sled 28 has a transverse slot 40defined therein which is dimensioned and configured to releasably retainan upturned flange 42 formed at the distal end of elongated actuationchannel 44 (FIG. 5). When the disposable loading unit 20 is placed intoretaining channel 14 and actuation sled 28 is disposed in itsproximal-most position, flange 42 releasably engages slot 40. Thus,movement of actuation channel 44 moves actuation sled 28. After astapling operation, when the disposable loading unit is removed from theretaining channel, flange 42 is easily disengaged from slot 40.

[0047] With continued reference to FIG. 5, actuation channel 44 isdefined by a base portion 45 and two parallel upstanding beams 46 and 48of elongate configuration. The distal ends of beams 46 and 48 arestaggered to match the staggered orientation of cam wedges 32 and 34,respectively. The proximal end of each beam projects rearwardly toengage the mounting block 49 that is associated with firing knob 50. Apair of slots 52 (only one of which is shown) are formed in mountingblock 49 for receiving the proximal end of each of the upstanding beams46, 48 of actuation channel 44 and the slots are provided with detents54 for engaging apertures 56 in the beam ends to lockingly retain thebeams in mounting block 49. In use, longitudinal movement of firing knob50 causes corresponding longitudinal translation of actuation channel 44and actuation sled 28.

[0048] Referring to FIGS. 2 and 4C, retention channel 14 includes a baseportion 60 and two upstanding parallel walls 62 and 64. Numericalindicia is imprinted on the walls 62, 64 of retention channel 14 toindicate the length of the staple line. Retention structures areprovided at the distal end of each of the walls 62, 64 to engagecorresponding structures provided on the disposable loading unit 20. Inparticular, notches 66 a and 66 b are provided for engagingcorresponding protuberances, such as protuberance 67, and slots 68 a and68 b are provided for engaging corresponding detents, such as detent 69.These structures inhibit lateral, longitudinal and perpendicularshifting of the cartridge 22 (and disposable loading unit 20) within theretaining channel 14. Ramped engagement slots 70 a and 70 b are alsodefined in the opposed walls of retention channel 14 for interactingwith a pair of opposed protuberances 72 a and 72 b (FIG. 5) to guide thedisposable loading unit 20 into retention channel 14 when loaded intosurgical stapler 10.

[0049] Referring again to FIG. 2, surgical stapler 10 further includesan elongate anvil support beam 80 which has a generally U-shapedcross-sectional configuration. Anvil support beam 80 and its associatedstructures are also referred to herein as the “anvil half-section”. Thedistal end portion 88 of the anvil support beam 80 in one embodiment istapered in height h in a distal direction to provide additional supportand reduce deflection during a staple firing operation. The proximal endportion 82 of support beam 80 has a notched area 84 for engaging a pairof corresponding detents 86 (only one of which is shown), which extendinto the cavity 15 of body portion 12 adjacent the proximal end thereof.The detents 86 are engaged when the cartridge half-section 11 a andanvil half-section 11 b are mated with one another. The distal endportion 88 of anvil support beam 80 is configured to support a preformedanvil plate 90 against which staples are driven and formed during astapling procedure.

[0050] Referring to FIGS. 7 and 8, anvil plate 90 is formed from aunitary piece of metal and is cold formed and stamped to define aplurality of staple forming recess or cups 91. Each staple formingrecess corresponds to a particular staple housed within cartridge 22.Anvil plate 90, as shown in FIG. 2, is provided with two opposed tangs92 a and 92 b which extend inwardly to engage complementary engagementslots 93 b (only one is shown) in anvil support beam 80 duringfabrication and assembly (see FIG. 10). The cross-sectionalconfiguration of anvil plate 90 is dimensioned to complement thecross-sectional geometry of support beam 80 (see FIG. 9). Moreparticularly, the cavity 97 which extends along the length of the anvilplate 90 corresponds to a similar channel formed in support beam 80.These areas accommodate shank 35 and knife blade 36 as it translatesdistally to form an incision in stapled body tissue during a staplingoperation.

[0051] A pair of rectangular apertures 95 a and 95 b are formed in anvilplate 90 adjacent the proximal end thereof for receiving a pair ofcorrespondingly positioned flanges or projections 96 a and 96 b whichproject upwardly away from the tissue contacting surface (see FIGS. 2and 4C). The interaction between aperture 95 a, 95 b and flanges 96 a,96 b ensures that the cartridge 22 and the anvil plate 90 are properlyaligned with one another during a stapling procedure. Flanges 96 a, 96 bare spaced proximally of tissue stop portion 61 of retention channel 14.Portion 61 and the distal edge 13 of handle portion, best seen in FIG.3, cooperate to prevent tissue from extending proximally.

[0052] Referring again to FIG. 2, the anvil half-section of surgicalstapler 10 further includes clamping handle 100 which is used tosecurely clamp tissue between the staple forming surface of anvil plate90 and the tissue contacting surface of cartridge 22. Clamping handle100 is pivotably mounted to anvil support beam 80 about a transversepivot pin which is not shown in the drawings. A pair of clamping hooks102 a and 102 b depend from clamping handle 100 for interacting with theU-shaped clamping beam 104 supported within the internal cavity definedin handle portion 12.

[0053] When stapler 10 is assembled prior to use, the notched area 84 atthe proximal end 82 of anvil support beam 80 is engaged with thecooperating detents 86 in the inner cavity 15 of body portion 12.Thereupon, the anvil half-section is mated with the cartridgehalf-section, and clamping handle 100 is disposed in the uprightunclamped position shown in FIG. 1A. Subsequently, when body tissue isproperly disposed between the staple forming surface of anvil plate 90and the tissue contacting surface of cartridge 22, the anvil halfsection is pivoted toward the cartridge half section, about the detentsin body portion 12, such that the distal ends of clamping hooks 102 aand 102 b are positioned immediately adjacent the proximal end of thebase of U-shaped clamping beam 104. Concomitantly, flanges 96 a and 96 bengage apertures 95 a and 95 b in anvil plate 90 to ensure properalignment of the anvil and the cartridge.

[0054] Then, to securely clamp the captured body tissue, clamping handle100 is pivoted from the position illustrated in FIG. 1A to that which isshown in FIG. 1B. At such a time, clamping hooks 102 a and 102 b engagethe base of clamping beam 104, locking the stapler in a clampedcondition. During clamping, the captured body tissue exerts acounter-force against the tissue contacting surface of cartridge 22 andthe fastener forming surface of the anvil plate 90, urging the twostructures apart. To overcome these forces and prevent the proximalportion 82 of anvil support beam 80 from bending, bearing surfaces aredefined within the retention channel 14 to support the compressiveforces generated during clamping. In particular, as illustrated in FIG.4A, opposed bearing shelves 110 a and 110 b are stamp formed in theopposed walls 62 and 64 of retention channel 14. The bearing shelves arepositioned to abut the medial section of anvil support beam 80 proximatethe clamping handle pivot point.

[0055] It may also be desirable to provide a locking mechanism toprevent reactuation of the apparatus after it has been actuated. Forexample, a locking member 120 shown in FIG. 11 can be positioned in theretaining channel 114. The locking member 120 is biased to an upwardengagement position and each end extends through a window 141, 143 inthe channel 114. A T-shaped member 124 is positioned between the camwedges 132, 134 to bias the hook portion 122 out of engagement with theactuation channel 144. Head portion 126 of T-shaped member 124 (FIG.11A) is initially retained in the cartridge by a pair of detents in thecartridge which extend into the knife slot When the stapler is actuated,head portion 126 of T-shaped member 124 in the knife slot. A second pairof detents (not shown) at the distal end of the knife slot engages headportion 126 of T-shaped member 124 to hold it at the distal end ofcartridge 122 when the cam wedges 132, 134 are advanced to the distalposition. When actuation channel 144 is retracted from the post-actuatedposition to the pre-actuated position, the T-shaped member 124 remainsforward allowing hook portion 122 to return to the upward position andextend through the window 141 in retaining channel 114 to engage edge143 (see FIGS. 12 and 13A) of actuation channel 144 to preventadvancement of the actuation channel. FIGS. 13A, 13B illustrate movementof the locking member 120 from an initial non-engaged position (FIG.13A) out of engagement with actuation channel 144 to an engaged position(FIG. 13B) in engagement with actuation channel 144 to prevent distalmovement thereof.

[0056] Referring now to FIGS. 14-16, there is illustrated, in sequentialorder, a staple firing operation in which a plurality of staples areejected from cartridge 22 and driven against the staple forming surfaceof anvil plate 90. In operation, prior to firing surgical stapler 10,actuation sled 28 is in the proximal-most position shown in FIG. 14. Atsuch a time, knife blade 36 is enclosed in a protective housing 25formed adjacent the proximal end of disposable loading unit 20. To firethe apparatus, firing knob 50 is moved in a distal direction.Accordingly, as illustrated in FIG. 15, actuation channel 44 drivesactuation sled 28 distally into and through cartridge 22. During itsdistal translation, the angled leading surfaces of cam wedges 32 and 34sequentially contact ejectors 26, urging them in a direction transverseto the direction of movement of actuation sled 28. As a result, theejectors 26 push the staples 24 from their individual slots, drivingeach staple into a respective staple forming cup 91 in anvil plate 90.

[0057] Sequential firing of the staples continues until actuation sled28 is advanced to the distal end of cartridge 22, at which time, all ofthe staples once housed within the cartridge 22 will have been ejected(see FIG. 16). Thereafter, the firing knob 50 is retracted to itsoriginal position, the cartridge and anvil sections are separated, andthe spent disposable loading unit 20 is removed from retaining channel14. Subsequently, a new, fully loaded disposable loading unit can bepositioned in retaining channel 14 such that the slot 40 of theactuation sled 28 engages the flange 42 of actuation channel 44 toenable re-use of the apparatus.

[0058] Although the subject apparatus has been described with respect topreferred embodiments, it will be readily apparent to those havingordinary skill in the art to which it appertains that changes andmodifications may be made thereto without departing from the spirit orscope of the subject apparatus as defined by the appended claims.

What is claimed is:
 1. A surgical stapler comprising: a) a first bodyportion supporting an anvil which defines a fastener forming surface; b)a second body portion configured to releasably mate with the first bodyportion; c) a disposable loading unit removably supported in the secondbody portion and including: i) a cartridge defining a plurality of slotsand a tissue contacting surface; ii) a plurality of surgical fastenersdisposed in the slots of the cartridge; iii) a plurality of ejectorspositioned adjacent the surgical fasteners; and iv) an actuatorconfigured to translate through the cartridge to sequentially interactwith the ejectors; d) an elongated actuation member mounted forlongitudinal movement within the second body portion and releasablyengaging the actuator, whereby longitudinal movement of the actuationmember causes the actuator to interact with the ejectors to drive thesurgical fasteners from the cartridge to be formed against the anvil.